How to Cascade-delete in MongoDB with Pymongo from the same collection

Question

Firstly, I have looked at these "solutions":

Cascade style delete in Mongoose

How to cascade delete in mongodb?

How to cascade delete document in mongodb?

What is the recommended equivalent of cascaded delete in MongoDB for N:M relationships?

But I still can't figure out how to do a cascade-style deletion. All the previous questions are using 2 separate collections, but in my case, everything is in a single collection.

So I have a schema that looks like this:

{
  "_id": "fafa76b0-40ef-4f38-af64-35992ceed119",
  "user": {
    "timestamp": "2022-10-22T13:53:43.042187",
    "name": "john2",
    "surname": "doe2",
    "email": "abcde1234@gmail.com",
    "phone": "+012345678987",
    "age": 18,
    "gender": "male",
    "nationality": "smth",
    "universityMajor": null,
    "preferences": null,
    "password": "e9cee71ab932fde863338d08be4de9dfe39ea049bdafb342ce659ec5450b69ae"
  },
  "postings": [
    {
      "id": "55412a9a-8efb-4213-90a4-efd693937f4a",
      "timestamp": "2022-10-22T13:53:43.043187",
      "title": "new posting 3",
      "totalNumOfRoommates": 2
    },
    {
      "id": "c3840cb9-4066-47ee-84db-404970c2e067",
      "timestamp": "2022-10-22T13:53:43.043187",
      "title": "new posting 4",
      "totalNumOfRoommates": 20
    },
    {
      "id": "e76d4dbd-02cb-41ca-a3f4-5204bf94611d",
      "timestamp": "2022-10-24",
      "title": "test Update4",
      "totalNumOfRoommates": 15,
      "price": 2500
    }
  ],
  "starredPostings": [
    "7d31d7d3-28ac-47b7-91bb-bd9a1d5954fe"
  ]
}

The postings array holds posting objects, each object has its own unique ID.

Then there's starredPostings which simply stores the ID of a posting object in another document.

What I want is that when I delete a document, let's call it document X, I want the IDs of all of the postings in document X to be removed from starredPostings in other documents

P.S: I am using FastAPI and Pymongo